This invention relates to devices and processes for treating aortic aneurysms (abdominal aortic aneurysms, thoracic aortic aneurysms, and thoracoabdominal aortic aneurysms). More particularly, the invention relates to devices and techniques for securing a graft to reinforce the aorta and reattach branching vessels that would otherwise be occluded. In addition, the invention addresses other treatment modalities involving reattaching branching vessels to the reinforcing graft. These include aortic root replacements for aortic dissections in which the left and right coronary arteries must be reattached to the replacement graft, and extracranial carotid aneurysm repair involving reattaching the internal carotid artery and/or the external carotid artery to a replacement graft. More particularly, this invention applies to all aneurysm treatment regimens involving attaching a reinforcing graft or replacement graft to isolate or remove the aneurysm and reattach branching vessels that would otherwise be occluded or separated. Embodiments of the invention enable rapidly securing grafts to the vasculature without the need to suture the graft to the host vessel wall, or to stop or re-route blood flow through the host vessel to reattach branching vessels.
Current techniques for producing anastomoses during aortic aneurysm procedures involve interrupting blood flow for a prolonged period of time to suture, clip, or staple a graft to the aorta. Interrupting blood flow is associated with substantial morbidity and mortality. Less invasive attempts at treating aortic aneurysms involve percutaneously deploying grafts into the abdominal aorta or thoracic aorta and securing the grafts with hooks or stents. Most of these less invasive approaches occlude blood flow while balloon catheters are used to position and expand the securing components into contact with the vessel. In addition, these approaches do not address branching vessels that can be occluded when grafts extend past the branching vessels to isolate the aneurysm from blood flow.
Attempts to automate formation of sutureless anastomoses have led to mechanical stapling devices. Mechanical stapling devices have been proposed for creating end-end anastomoses between the open ends of transected vessels. Berggren et al. propose an automatic stapling device for use in microsurgery (U.S. Pat. Nos. 4,607,637, 4,624,257, 4,917,090, and 4,917,091). This stapling device has mating sections containing pins that are locked together after the vessel ends are fed through lumens in the sections and everted over the pins. This stapling device maintains intima-to-intima apposition for the severed vessel ends but has a large profile and requires impaling the everted vessel wall with the pins. Sakura describes a mechanical end-end stapling device designed to reattach severed vessels (U.S. Pat. No. 4,214,587). This device has a wire wound into a zig-zag pattern to permit radial motion and contains pins bonded to the wire that are used to penetrate tissue. One vessel end is everted over and secured to the pins of the end-end stapling device, and the other vessel end is advanced over the end-end stapling device and attached with the pins. Sauer et al. proposes another mechanical end-end device that inserts mating pieces into each open end of a severed vessel (U.S. Pat. No. 5,503,635). Once positioned, the mating pieces snap together thereby bonding the vessel ends. These end-end devices are amenable to reattaching severed vessels but are not suitable to producing end-end anastomoses between a graft and an intact vessel, especially when exposure to the vessel is limited.
Mechanical stapling devices have also been proposed for end-side anastomoses. These devices are designed to insert bypass grafts, attached to the mechanical devices, into the host vessel through a large incision and secure the bypass graft to the host vessel. Kaster describes vascular stapling apparatus for producing end-side anastomoses (U.S. Pat. Nos. 4,366,819, 4,368,736, and 5,234,447). Kaster""s end-side apparatus is inserted through a large incision in the host vessel wall. The apparatus has an inner flange that is placed against the interior of the vessel wall, and a locking ring that is affixed to the fitting and contains spikes that penetrate into the vessel thereby securing the apparatus to the vessel wall. The bypass graft is itself secured to the apparatus in the everted or non-everted position through the use of spikes incorporated in the apparatus design.
U.S. Surgical has developed automatic clip appliers that replace suture stitches with clips (U.S. Pat. Nos. 5,868,761, 5,868,759, and 5,779,718). These clipping devices have been demonstrated to reduce the time required when producing the anastomosis but still involve making a large incision through the host vessel wall. As a result, blood flow through the host vessel must be interrupted while creating the anastomoses.
Gifford et al. provides end-side stapling devices (U.S. Pat. No. 5,695,504) that secure harvested vessels to host vessel walls maintaining intima to intima apposition. This stapling device is also inserted through a large incision in the host vessel wall and uses staples incorporated in the device to penetrate into tissue and secure the bypass graft to the host vessel.
Walsh et al. proposes a similar end-side stapling device (U.S. Pat. Nos. 4,657,019, 4,787,386, and 4,917,087). This end-side device has a ring with tissue piercing pins. The bypass graft is everted over the ring; then, the pins penetrate the bypass graft thereby securing the bypass graft to the ring. The ring is inserted through a large incision created in the host vessel wall and the tissue piercing pins are used to puncture the host vessel wall. A clip is then used to prevent dislodgment of the ring relative to the host vessel.
The previously described end-side stapling devices require insertion through a large incision, which dictates that blood flow through the host vessel must be interrupted during the process. Even so, these and other clipping and stapling end-side anastomotic devices require significant time to create the anastomosis. Interruption of blood flow for a prolonged period of time increases the morbidity and mortality of grafting procedures, especially during aortic aneurysm repair.
A need thus exists for fittings, grafts, and delivery systems capable of quickly producing an anastomosis between a graft and a host vessel or reattaching branching vessels with minimal interruption of blood flow. These anastomoses must withstand the pressure exerted by the pumping heart and ensure blood does not leak from the anastomoses into the thoracic cavity, abdominal cavity, or other region exterior to the vessel wall. In addition, these anastomoses must prevent dislodgment even when the graft is subject to external forces or motion of the aorta.
The invention provides systems and components for improved treatment for aneurysms that extend to bifurcations and/or envelop branching vessels, especially aortic aneurysms. The systems enable a physician to quickly and accurately position and secure a reinforcing graft. In addition, the invention provides processes to reattach branching vessels to a reinforcing graft positioned within and secured to a host vessel while minimizing the interruption of blood flow to the branching vessel during the procedure.
The invention provides extension grafts that are configured to lengthen a branching vessel or other host vessel which may be too short to reach the desired anastomosis site. The extension grafts also provide a mechanism to expedite reattaching the branching vessel to the reinforcing graft or reestablish blood flow to a branching vessel without the need to cut the branching vessel. The invention includes reinforcing grafts that incorporate branches containing end-end fittings inserted into and secured to branching vessels without cutting the branching vessels.
End-end fittings are provided to secure reinforcing grafts or extension grafts to host vessels. Once positioned within the host vessel, the end-end fittings are secured to the host vessel by compressing the host vessel against the end-end fitting using retaining rings, strands of suture, or stitches placed around the host vessel at the end-end fitting interface.
The invention provides end-side fittings capable of securing branching vessels or extension grafts to the side of a reinforcing graft and/or host vessel. The end-side fitting embodiments can be configured to produce anastomoses between branching vessels and host vessels such that only the endothelial layer of the branching vessel is exposed to blood flow. In addition, end-side fitting embodiments are provided that do not require a delivery system to insert the end-side fitting through the reinforcing graft wall and/or host vessel wall.
The delivery systems of the invention enable inserting an end-side fitting,and branching vessel combination or an extension graft through a host vessel wall, and in many cases also a reinforcing graft, without interrupting blood flow through the host vessel. In addition, the delivery systems of the invention enable inserting a reinforcing graft through a host vessel wall. One delivery system embodiment is a combination of a tear-away sheath, dilator, guidewire, and needle designed to be inserted into the host vessel at the desired anastomosis site. The fitting and branching vessel combination is inserted through the tear-away sheath into the interior of the host vessel. After reattaching the branching vessel, the hub and valve of the tear-away sheath are split and the sheath is then separated and removed from around the branching vessel. A plunger is used to insert the branching vessel and fitting combination through the sheath and past the host vessel wall and graft wall. The plunger also protects the branching vessel during insertion, especially when advancing past the hemostatic valve.
An alternative delivery system involves advancing a fitting directly through a puncture in the host vessel wall and graft without stopping or re-routing blood flow. The fitting is partially inserted through an incision and rotated past the host vessel wall and graft, into the interior of the host vessel. Optionally, a guidewire can serve as a passage to rotate and advance the fitting past the host vessel wall and graft, and into the interior of the host vessel. Once inside the host vessel, the fitting is secured, thereby attaching the branching vessel to the host vessel.